You, Will Prowse, and Hobotech should all get together and have an insane conversation. Thanks man.

Dude, you are tied with Dave Poz, Tin Hat Ranch, and Will Prose for the best info/teaching in solar. Each of you excel over the others in your specific areas. This is meant as a complement. I prefer your speed and detail of info and diagrams are fantastic! I learned more detail and had holes in areas I thought I knew filled in after watching your videos!

Great video Nate. Basic electricity at its finest!

I'm so glad you're continuing with this series. It helps so many people.

You are a very good teacher. Thank you from the bottom of my heart. *.*

Best tutorials on the Internet great job!

Thank you for all you do to help people. I do not have my 41 motor home.

Nate, Thanks for all the work you two have done!

Best explanation of solar panels I've seen yet!! Thanks!!

A brilliant video, thanks for the awesome explanation of the results of combining different sized panels.

Thanks for the easy to follow explanations. I am learning so much.

Legend mate. That has simplified everything. I was worried I would lose watts on my mismatched panels. Now I know correct wiring

I appreciate the repetition of the formulas and the sums. I learn faster that way. Thank you, sir!

You are the best at this. You actually have real life installs verse talking about "how it can be done" from inside a room. Thank you very much for this great information

clear and concise ..thanks for all your hard word ..its much appreciated

This is one of the best solar videos I’ve seen. Thank you!

Wonderful teaching! Very helpful. This is what I was looking for!

Wow. Very informative. I will watch more of your videos...under ideal conditions.

your explanations are so clear. thank you

Watched 3 of your videos and think you are an excellent instructor who is clear and totally understandable! Bravo

Nate, you have one of the best DIY sites I have visited. Love your style. I get Volts /Watts / Amps / Parallel / Series. I was missing the part that the MPPT controller actually made the adjustments. Cool, got it.

Waiting on the future video about when in line fuses are needed. Thanks for good info.

Hi Nate. Really appreciate your efforts to help us all DIY. I have watched all of your DIY solar videos, some of them multiple times to help me learn solar/RV electrical. I've learned a lot but I'm still not 100% confident in my decisions. I would like to have 2 arrays for my RV. One array will have 4 Renogy 100W (18.6V, 5.38A) panels run in S/P 2/2. These panels will be placed on the ground to get better angles to the sun and to help avoid shading. The other set of panels will be placed on the roof of the RV to allow us to charge while on the road (and in camp), but since placement is more challenging they may get obstructed. I was originally looking at the Renogy 200W but given the array specification differences it seems that their performance would be too low. So based on your advice I changed to using the Rich Solar 200W (37.6V, 5.32A) panels wired in parallel, which if I have done my calculations correctly should get us to 99.8% efficiency. Can you please double-check my logic on this? Thanks. Now for my "real" question - do you think I should use 2 solar charge controllers (say a Victron 100/50 and a Victron 150/60) or would we be better served using one solar charge converter (say a Victron 150/100). The price difference between the two S.C.C. approaches is negligible. Thanks for whatever advice you can provide! Jim

Finally found a video explaining this! Thank you!

The best explanation by far. Thanks!

First video explaining solar configuration - you have done a great job creating this. Well done

The Series has been great! Think I've watched everything! Certainly picked up a lot of clue, from tools, to when to fuse on the roof. What about discussing East / West panels? (when one has no suitable house roof pointing to the equator). I understand that this could be more desirable as one can catch both the early and late sun rays. One thing you don't seem to have mentioned is that if there is shade on a string - it affects the whole strings production of power - so having a well chosen placement of a mix of Series and Parallel panels can be the wisest configuration. Lastly (back to East/West configs), if there is less sun on an area - does this affect the voltage or the amperage of the string? Oh - the hour long video with your friends RV - four panels down each side in series, why that format? I think I'd put the four at the front in series and the four at the back in series - so parking with one end in shade gives at least one good string. The Left & Right strings is primarily beneficial if in the complete open with the RV parked North/South. Perhaps have a method of switching between the two layouts?

Thanks so much for this! Saved my bacon again today. Please keep 'em coming.

Thank for the video! After watching it an doing some comparisons, I realized I'd get the best watt output if I wired them all in series. Ended up with 250 watts vs previously I was getting something like 100 watts.

Great videos, direct a quick to the point , and extremely informative, thumbs up every time!!

Thanks for this video This one give me good knowledge

The diagrams help it sink in Nate thank you, I’ll just watch this video another 3 or 10 times and get a new piece of paper and start again. I usually get professionals to do my electrical work but I want to DIY to understand what I’ve got for remote travel troubleshooting if something happens.

That was the question I’ve been asking, now that I know how to figure it I can decide what solar panels I need to buy thank you

excellent work, very comprehensive and to the point.

Excellent presentation, well explained, thank you.

The last example of adding an additional panel that cuts output in half is super informative.

Man, really great info, love the way you break it down for us!

Thank you so much for making this make sense.

Your video is very good. Explainations and diagrams are spot on!!👍👍 Math is also awsome. The one problem I have is you keep calling it watt's law, the correct terminology is ohm's law. I say this with 49 years of electrical experience. I am not trying to bash your presentation because it is quite good, just putting this out there for information purposes. Keep up the great work!!

Thanks, with your help I able to solve my problems

I came across your KZfaq site. Very good explanations on the panels and systems. You have done a very good job on the educational aspects of the web site. Using ABYC as a guide is also brilliant. I wish I had found this 5 years ago when I was exploring solar. I am retired, used to run a fire LAB and I am now bored a lot. I set up a test rig a few years ago to verify the different types of 12V 100W panels and types of controllers. I used a 4 tube Florent ceiling light fixture for a constant light source. I put the panels on the light source and fed them through both PWM/MPPT controllers. Measured all the outputs, charging times, loads etc. after a few weeks of testing I came up with the best configuration. I charged a 950 Ah lead acid battery, then I would use a 2Kw Inverter to power up 3 100W light bulbs and drained the battery to 11V, then charged it back full. After doing this 15-20 times I was able to calculate the power generation of each panel and efficiency of the controllers. Then moved outside to do sun source testing. Lots of fun was had. I have a 76 VW Camper. I installed the test solar system on the bus. I have a pair 100W panels in series feeding a cheap MMPT controller. I live in the Pacific NW and all the rain and clouds here are not optimum for solar. Plus the latitude of 48 Deg north means the sun angle is low. The standard 12v panel would not reach charging levels all the time. My testing showed only a couple hours a day they would produce charging voltage when in parallel. So I put the panels in series so when each panel made 7-8 Volts the sum of the voltages will start the charging cycle. Current is low 5-7 amps, but acceptable for this application and this actually works very well in this area. I have a pair of 650Ah Lead acid batteries and they stay full with the system. When the batteries are full the controller shuts off the charge and the panels go to open circuit voltage. The bus is parked most of the time and not used much. The MPPT controller has a switched load, (like they all do) I am looking to use the excess solar panel power on a restive load after the batteries are full. Since the bus has a refrigerator that runs on Gas/DC/AC. I wired the switched output of the MPPT controller, to the Refrigerator electric heater (12V 1500W) through a diode. I have run this for a few weeks to see how the system will operate. The refrigerator stays cold and occasionally will freeze water on a bright day. This works very well to use the excess power generated so the panel does not sit around at open circuit voltage most of the time. But it's a manual operated, go push the button system. The power is way less than the 1500 watt design but just warm enough to boil the ammonia in the evaporator. I have also wired this into the cheap Chinese diesel heater, it will run on the solar panels alone after it is started and up to temp ( heater fans use 2.5-3.5 amps ) so it will operate on a bright day. It can't start on solar, since the glow plug on start draws 10 amps but after the glow plug cuts out the fan blowers work fine on solar. Question for you.... Do you know of any MPPT controller that will automatically switch to the "external load mode" when the batteries are full. Or a way to automatically switch with a relay to off load the excess power. If the refrigerator load could be automatically switched, it would run on the solar panels when driving and the alternator is keeping the battery voltage above the MPPT cut off voltage. This is not all that important on this bus, but on larger solar systems, the excess power can be sent to the 1500W heater strip, or maybe a hot water heater element. . On larger RV's this could save the panels from the Open Circuit condition which is not good for the panels. . Thanks for your time, great job on the solar series.

Exactly what i searched! You are my man!!!

This video literally just helped me figure out the mathematic equation for my system. Under perfect factory testing conditions, ill be installing a 98% efficient system. I appreciate it sooo much!

What? You just save me from spending unnecessary different size of panel that was not gonna work for my solar array. Thank you. 👍🏼

This is a great video! Thank you for giving such a clear and in depth explanation!

Just an awesome explanation and so well put together. Thank you!

Great tutorial, you are a good teacher!

Exelent video. Was Very very helpful to me. Thanks alot!

Such a clear explanation- thank you. 👏

Thanks for very nice clarification

That's awesome. Thank you, Nate.

Thanks for the great and expertly explained information! I wish I’d seen this sooner, but glad I didn’t see it any later

Thanks again for great details!

New to the channel and solar,(subliminal message) "VxA=W".lol great video.thanks for the panel explanation, was curious on this subject

Wow, you clearly put a LOT of time into this (script, diagrams, filming, editing, etc.)! This is the best video on explaining the pros / cons and how-to on combining mismatched cells / panels. THANKS!!!

Excellent video, very informative. Thanks 👍🏻

Hi Nate, love your channel. I have learned so much. My question is when you talk about a 20v panel are you using the VOC number on the panel specifications. Thanks

freaking fantastic. i have space for 4 (maybe 6) x 270 or 300 watt panels and was thinking to add some in the extra space. this is so fruitful to know these plans. for example if i had space for 4 matched panels then added in 2 smaller extra ones but used a different controller to feed the same battery bank how would that work?

This was a great guide :) I had been pondering on similar problem when using 24v system and using 12v light bulbs and what would happen with mismatched bulbs in series to make 12v work on 24v and came to similar conclusions, had not thought about it when it comes to solar panels and it would be simlar problems... But it is logical when you think about it :)

Super helpful thank you so much!

Excellent. Easy to understand. Thank you for making it easy ☮️🙏☯️

Best explanation on this topic I have run across, and exactly the information I needed to help me configure my ever growing solar system...thank you....aloha

Brilliant explanation

Thanks I new this but still I wired them wrong. Thanks to your great video I now get more watts out of the same panels. Brains need to be refreshed now and then.

Good explanation and great graphics! 👍😎

Excellent video and blog post, thank you. Today I tested my new Renogy 100W and 50W panels wired in series and in parallel. I will mount two of these pairs, each connected to its own MPPT charge controller, either side of my yacht's main sail. Based on the panel specs (same Vmp but different Imp) I expected that wiring them in parallel would produce more power output. Surprisingly, when I measured the amps in series they were double what I expected - 5.2A instead of the 2.69A Imp of the smaller 50W panel?! Any idea what is going on here?

I am using 3 solar panels in parallel to charge a 12v car battery. This is used to power up 3-4 leds street lights on the wall. The lights used to stay on till about 4am. The solar panels are not of same size so I think the wire is not right to get the battery charged full. This video helped me to understand the wiring. I will try to correct it.

I have tested the same and yes this happens. In order to have proper solar array,we must use equal wattage,voltage,amps and type of panels.

Thank you, this was very helpful.

I'm researching solar set up for my RV and ran across your channel. Thank you for the very helpful content. I currently have the 190 watt overlander solar kit that came factory installed on my travel trailer. It came with a port/plug on the trailer to plug in a portable solar panel. My question is what impact or considerations should I take into account if I wanted to supplement my overlander solar with a portable panel for some additional solar when needed? Would it have a negative impact on the entire system if it's a smaller panel??? Thank you in advance.

Hi Nate. Until recently, I had two solar chargers to charge the batteries. Four modules on each, namely the new Q cells string parallel on the Epsolar tracer 6415AN, and the mixed brand cells also parallel on the Epsolar eTracer 6415BND. Each branch was tied in parallel. Now I bought a Victron energy smartsolar MPPT 150/100 and the question for you now is how to tie the panels if you can advise me. Sorry for the bad English and nice greetings from Slovenia.

Great info.i heard that battleborn has their own solar panels.have you received any information on them.

This is a great explanation.

Thanks!

very nicely explained. very helpful

Great vid, do you know of an online or spreadsheet tool that you can quickly plug in your existing array and then play with what-if scenarios? Reason I ask I see some vendors with B grade panels for sale and I'd like to add to my SunPower system. Thanks

Thanks for this Video! When making these calculations and for adding additional panel to the array, is it best to use Voc or Vmp? I have plenty of mppt capacity, especially on the voltage front with a 100V/30A victron mppt with a 24v LiFePo4 battery...

Awesome! Thank you.

I needed this. OMG! Thank you...

That was very helpful!

Very helpful, very informative 👍 👍👍

Hi there. Thank you for this video! It was really helpful with deciding how to set up my solar on my RV. I had a question maybe you can answer... I currently have 2 x 100w panels and 2 x 175w panels on the roof of my trailer. I've wired them in series-parallel as you demonstrated in 7:10. However, I didn't account for the fact that because my panels are near my roof AC, there is usually a high chance of shade on at least one of the panels at any given time unless the sun is straight above. In my scenario would it have been better to just get 4 x 100w panels (4 x 175w won't fit) and wired them all in parallel? These are all going to a single MPPT charge controller.

Very helpful, thanks. How does using something like SolarEdge power optimizers change the equation? I’m assuming it could be substantial as they regulate the power between individual panels helping minimize the effects of partial shade etc. Would appreciate your thoughts. Thanks

Thanks Bud, I now know why my 160 watt and 100 watt roof panels only produce 11 amps. When plugged in separately I can see 14 amps in ideal conditions. I have a Timber Ridge 24 RKS with the factory solar kit and the portable solar panel plug on the side. When I plug my Go Power 120 watt portable into the side port the two controllers fight and take turns shutting down. I finally bypassed the portable panel controller and plugged it into the third plug on the roof using only one controller and now I can see 15 amps from the 3 panels instead of the 20 amps I can get when totalling individually. I guess I will replace the 100 watt panel with a matching 160 watt panel on the roof and hope my 120 portable has the same voltage. I was wrong to assume the dealer knew what they were doing, lesson learned.

Thanks Nate for providing this very comprehensive and understandable information. I have 48V electric riding mower which I'm setting up with solar, so that it will charge as it is running, thereby extending my range. Unfortunately, through using your online PV/mppt calculator I found out that my pv voltage has to be 5V above that of the 48V battery bank. From a lack of knowledge I assumed I could just have one 100W solar panel push wattage into the bank while driving it. Why does a trickle charging solar panel (the little ones you can buy for RV batteries running at about 10 watts) work on a 12V rv battery, since the voltage of that little panel would be way below the 12V of the rv battery. In my case I'd have to provide at least 300 watts of solar panels (there is no way I can fit that many panels on the support rack I'm building on the mower) in order to actuate the dang mppt controller. Is there any alternative way to push the single 100W into the 48V bank? I see this as a major drawback over a 12V or 24V system in some applications. There should be devices that up-converts (inversion from +- 18V PV voltage to +- 48V battery bank voltage) PV voltage to activate the charger at any time? Any suggestions would be greatly appreciated since I've already put in a lot of time into this built.

excellent video thank you very much!!! 👍

Thanks for explaining all detail information

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I'd like to see an addendum to this video in which you explain the use of separate mini-controllers (I'm not sure that my terminology is correct, but I think you understand the gist of my request).

I am learning so much from this channel, although there are some things that are still a bit fuzzy in my head. QQ. I own 3-160w EC panels (18.2v*8.8a) and 2-100w panels (17.1v*5.9a) I was looking for a way to combine them with minimal loss. I think the best possible way under this scenario would be to put them all in a parallel configuration. Combined AMPs 38.2 * Lowest Volt 17.1 = 653.22 out a 680w. Is that math correct?

I appreciate this information... about keeping the panels the same size... and what you explained about adding in a smaller panel, it reduces the overall performance. My question is If smaller panels are at the beginning(negative end)of a series, then larger panels are added, is the math the same?

solid explanation bro- fantastic

Great stuff! Thanks

Best ever! Thank you

Good video as usual. Could you maybe consider making videos on how to use software tools to add batteries and assign inverters as master inverter etc .

Good video! Just wondering what software do you use to make the diagram?

Pretty fast. Top. Very good.

Hi Nate! Awesome video! Really helpful! I still have a doubt if you can help me! I live on a boat, with a battery bank of 700A with 6 solar panels adding a total of 740W. They are different Wtts but very similar Vts. All connected in parallel. Question is: what’s more important to charge my batteries, full 740Watts or all the Amps I can get from the parallel connection? TIA! Cheers.

What a impressif and informatif video to get on the track, Thank you ! Question : if my understanding is right, can i connect in series 6 X 200 w Renogy panels on 10 Awg cables with a victron charge controller 170-100, and what about the Mc4 connectors good for 30 amp ? I made my calculation on 95% efficiency of the panels but as we all know i will be lower than that. Thank you!

Point of contention: you said, "lowest common denominator," but that cannot be what you meant based on your math. I believe that you meant 'lowest volts (or amp) rating," because the lowest common denominator between 25 and 20 is 5 for the volts [wired in parallel] (and between 8 and 5 is 1 for the amps [wired in series]). Barring that, I am learning a lot through this video. Thanks!